64 MtfceUanea Curiofa. 



gle Ac the L Ac d (piBC d~bc a) with 

 its legs AC, c D being known, the fide A d, 

 will be known ^ and in like manner £ c in the 

 triangle EDC 



Note, that in this Problem, as alfo in the 

 firft and fecond, if the two ftations fall in a 

 right line with either of the given Objects : 

 the locus of A, or £, being a circle, the par- 

 ticular point of A, or £, cannot be determined 

 from the things given. 



As to the other cafes of this third Problem, 

 \vherein A and £, may fliift places, u e. 0 nly 

 DFE, may be vifible at A^ and only a, c, 

 at £ ; or wherein 5, D, £, may be vifible at 

 A , and only c, F, ^, at £ ^ or wherein a may 

 be of one fide of the quadrilateral, and £ on 

 the other; or one of the ftations within the 

 quadrilateral, and the other without it : I 

 fhall for brevity fake omit the Figures, and 

 diverfity of the Sines + and— in the calcula- 

 tion, and pfefume that the Surveyor will ea- 

 fily direft himfelf in thofe cafes, by what 1ms 

 been faid. 



The folution of this third Problem is gene- 

 ral, and ferves alfo for both the precedent. 

 For fuppofe c D, the fame point in the laft fi- 

 gure, and it gives the folution of the fecond 

 Problem: but if B c be fuppos'd the fame 

 points with .£>, i 7 , by proceeding as in the laft, 

 you may dire&ly folve the firft Problem. 



A 



